The Fukushima nuclear power plant incident has made everyone acutely aware of how dangerous nuclear energy can be. Everyone knows that radiation is very poisonous, and is not save at any dosage level. But I myself was a bit perplexed about the effect that radioactive iodine can have on humans. So I had to go back and do a bit of homework on it.
The form of iodine that is radioactive is an isotope, known as iodine-131 or radioiodine. It has a half-life of approximately 8 days. Although it is used mostly in medical and pharmaceutical applications, it is most notorious for its role as a major radioactive agent present in nuclear fission products. It was a leading cause of the deleterious health effects from open-air atomic bomb testing in the 1950’s, the Chernobyl nuclear disaster, and is a dreaded concern in reference to the recent Japanese nuclear crisis.
The reason for this is that I-131 is major product of fission reactions with uranium, plutonium and indirectly thorium, comprising approximately 3% of the total products of fission (by weight). Due to its mechanism of beta decay, I-131 is very powerful in its mutagenic and toxic effects on cells that it penetrates, as well as other cells up to a few millimeters away. Ironically, high doses of I-131 are sometimes less dangerous than lower doses, because they tend to kill thyroid tissues which would other become malignant due to the radiation exposure. So for therapeutic use, I-131 is used in large or maximal treatment doses. Moderate dosages seem to be absorbed in the thyroid gland, which often leads to thyroid cancer, especially in children.
Iodine in food is absorbed and concentrated in the thyroid gland where it is needed for optimal thyroid function. If iodine-131 is present in high levels due to radioactive fallout, it can be absorbed through contaminated food, and will accumulate in the thyroid. As it goes through radioactive decay, it can cause major damage to the thyroid. The biggest risk from exposure to high levels of radioiodine is the occurrence of radiogenic thyroid cancer later in life. There is also a risk of benign growths and thyroiditis (inflammation of the thyroid).
The incidence of thyroid cancer due to exposure to iodine-131 seems to lessen as the age of victims increases. Most of the risk estimates are based on studies on which the radiation exposure victims were children or teenagers. When adults are exposed, epidemiologists have had a hard time establishing a statistically significant difference in thyroid disease rates between exposed and unexposed populations.
The risk of thyroid cancer can be reduced by the consumption of iodine supplements. The thyroid will not absorb much of the radioiodine if it is saturated with non-radioactive iodine. The idea is to raise the safe iodine levels in the body so that the uptake of the radioactive iodine is reduced as much as possible. In the United States, the highest recorded I-131 fallout doses occurred in the 1950’s and 1960’s to children that drank milk that was contaminated by ground testing of nuclear weapons.
For catastrophic nuclear incidents, it is recommended to take potassium iodide to saturate the thyroid gland, usually 130 mg in one dose, or 65 mg twice in one day. But one should be sure not to take this on an extended basis because the iodide can cause severe side effects over a long-term basis. This dosage is approximately 700 times more than a nutritional dose of iodide, which is around 0.15 mg per day.
This is important because there are some reports that there are radionuclides from Japan being blown over the United States. So, despite the media blackout on any news about these developments, people around the world should be protecting themselves from the radioactive fallout that is being dispersed around the world. Do NOT depend on the mainstream media to tell you the truth about this, as they are trying their best to keep the people calm.